Brake mechanism



Jan'. 2, v1934 R. s. SANFORD BRAKE MECHANISM Original Filed Nov. 2, 1925 4 INVENITPR R' y 5. SAN FORD ATTORNEY Reissued Jan. 2, 1934 OFFICE BRAKE MECHANISM Roy S. Sanford, South Bend, ImL, assignor to Bendix Brake Company, a corporation of Illinois Original No. 1,606,045, dated November 9, 1926,

Serial No. 66,271, November 2, 1925. Applicationv for reissue August 9, 1930. Serial No.

10 Claims.

trated diagrammatically as embodied in an automobile. v

Ordinarily, when air brakes or other power brakes are applied to an automobile, there are auxiliary manual connections for applying the brakes when the power fails, but there is no direct connection from the brakes back to the pedal or other devicewhich controls the application oi power. As the manual connections are used very seldom, there is noway by which the driver is warned of excessive wear of the brakes, in relation to the manual connections, unlesshe inspects them periodically (which very few drivers do), until he tries to-apply them manually and his brakes fail to hold. Long before the brakesare so worn that they will not hold when applied by power, they are worn badly enough so that the pedal reaches the floor board without applying the brakes when, usually'in a serious emergency, .the power fails and the driver tries in vain to use the auxiliary manual connections. An important object of the present invention is to warn the driver'of the wear in his brakes 'before the manual connections become inoperative, by controlling the power through avalve or equivalent device interposed in the manual connections, and preferably forming a lost motion tension element betweenthe pedal or the like and the brake cam or equivalent manuallyoperated brake-applying means. Upon failure of power, the valve thus acts as one of the tension elements in'the manual connections effecting the emergency braking.

The valve shifts as the brakes go on, not ac-- cording to the powerapplication, but according to the slack in the manual connections. Therefore, when power application of the brakes has worn them to the point-where the manual con-- nections are becoming ineilective, the driver finds his control pedal reaching the floor board before he can apply full power to the brakes, and

knows that adjustment or relining is necessary to make manual braking effective.

The above and other objects and features of the invention, including various novel combinations 01 parts and desirable particular constructions,- will be apparent from the following description of one illustrative embodiment shown in the accompanying drawing, in which:

The figure is a diagrammatic view, partly in side elevation and partly in vertical longitudinal section, and with the parts out of proportion as to size, oLthe automobile.

'ated by links or other connections 22 parts of the brake mechanism of an V when the brake has been applied proportionately- (Cl. 188-152) This invention relates to brakes, and is illus--' Themechanism includes one or more brakes including friction parts it, operated either by a, cam or other mechanical device 12, or alternatively by a cylinder and piston or equivalent fluid-powermeans 14 against the resistance of the usual return spring 15.

Fluid under pressure is supplied to the fluidpower means 14 from a reservoir 16. through flexible conduits 18 and 20. Device 12 is operand 24 from -a pedal or other controlling member 26.

According to the present invention, there is interposed between conduits 18 and 20 a novel valve 28 forming a tension element connecting links 22 and 24. This valve includes a casing 30 having a passage 32 communicating with conduit 20, a passage 34 communicating with an exhaust conduit 36, and a passage 38 communicating with conduit 18. I Casing 30 forms a cylinder for a plunger 40 having a cross passage 42 connecting passages 32 and 34 when the plunger is at the right end of its stroke, and a second cross passage 44 connecting passages 32 and 38 when plunger 40 is at'the left end of its stroke. Plunger 40 is urged toward the right by'a spring 46, much lighter than spring 15 andits two extreme positions are positively deter-- mined by a collar or enlargement 48 engaging shoulders in the bore of casing 30.

Casing 30 is directly connected by a pivot to link-22, while plunger 40 is pivoted by a slotted connection 53 to a lever 52 pivoted at 54 to link 24, and fulcrumed at 56 on an extension of casing 30.

Now suppose that pedal 26 isdepressed when there is no compressed air in reservoir 16. Evidently, aite'r spring 46 is compressed and enlargement 48 seats against the shoulder at the left or its stroke the air will rush through passage'44 to cylinder 14, applying the brake by power. As the friction parts 10 separate, there being no resistance other than the brake springs already overcome by the fluid power of the air, cam 12 will follow, by virtue of the expansion of spring 46 moving the valve casing, turning just the same as if it were applying the brake. This follow-up movement of the valve casing tends to open the exhaust passage 42. So long as thebrake has not worn too much, this will not happen, although spring '46 will automatically shut oil passage 44 to the depression of the pedal whichis held in its intermediate position, the brakes being'held hi applied position. when the pedal 26 is released, spring 46 opens the exhaust passage 6 and releases the brake. I

If, however, the brake lining has worn so much that the brakes cannot be applied manually, even i .though they could still be applied by power, pedal '28 will reach the floor board, on account of the s'hiftingof the valve permitted by the turning of cam 12, before the brakes are fully applied.

When the floor board is reachedpreventing furtherapplication of the power, the driver has his i attention called forcibly to the necessity of adlusting or relining his brakes by his inability to further apply them. Just as if the pedal and not thepower means was actually apply the brakes. And consequently, the next time he actuaily does have to apply the brakes manually,

connections.

he will not be disagreeably surprised to find that he can not do it.

while one illustrative embodiment has been described in detail,- it isnotmy intention to limit the "scope of the invention to that particular embodiment, or otherwise than by the terms 'of the appended claims.

1. Brake-operating mechanism comprising, in combination, two separate brake-applying devices, power means for operating one device. a

controlling member, and means for controlling the power of thepower means and which isoperated partly by the controlling member and' partly by the'other of the brake-applying devices.

. 2. Brake-operatingmechanism comprising, in combinatiom'two separate brake-applying de vices, fluid-power means for operating one device a controlling member, and a fluid valve for con trolling the power of the fluid-power means and which is operated partly by the controlling memberand partly by the other of the brake-applying devices.

v 3.. Brake mechanism comprising, in combina tion, friction'parts, power means for applying the friction parts, separate manually-operated connections for applying the frictionparts, and

a controlling device for'the power forming a force-transmitting element in said connections and operated by the application of force to said 4. Brake mechanism comprising, in combination, friction parts, fluid-power means for applying the friction parts, separate manually connections for applying the friction parts,and a controlling I ve ior the fluid-power forming a force transmitting element in said connections and operated, by the application- -of force to said connections.

5. Brake mechanism comprising, in combination, friction parts, a cam for applying the friction parts, a fluid-power device separately engaging and applying the friction parts, connections for operating the cam, and means for supplying fluid \mder pressure tosaid device including a valve forming a part of said connections.

'6. Brake. mechanism. comprising, in combination, friction parts, a cam for applying the friction parts. afluid-power device separately enging and appiying'the friction parts, connections for operating the cam, and means for supplying fluid under pressure to saidfdevice including a valve operated by said connections."

'1. Brake mechanism comprising, in combination, friction parts, a mechanical expanding device and applyingthe friction parts, a fluid-power expanding device separately enaging and applying the friction parts',;connections for operating themechanical device, and means for supplying fluid underpres'sure to said fluid-power device including a -.valve forming a part of said connections.

'8. Brake mechanism comprising in combin'ation, friction parts. a mechanical expanding device engaging and applyin riih friction parts, a fluid-power expanding device separately engaging and applying the friction parts; connections for operating the mechanical device, and

means for. supplying fluid under pressure to said fluid-power device including a valve operated "saidconnections.

Brakec, in combinarictionparts, a cam for applying the fricpar'ts,- a'fluid-powei": device separately enparts, connec- M means for sup- V a valve-forming atension element in ""d'cjonnec' tions.;j;

' 10 mechanism tion,-"frictionparts, a mechanical expanding de- ,vice andaim yi the friction parts.

a fluid-power expanding device separately eng mgjand applying the friction parts, connections for operating the mechanical device, and means for supplying fluid under pressure to said fluid-power deviceincluding a valve forming a connections.

tension element in said v ROY S. SANFORD.

comprising in combina- 

